Alexander M. Walker, MD, DrPH is Adjunct Professor of Epidemiology at Harvard School of Public Health, where he was formerly a professor and Chair of the Department of Epidemiology. His research encompasses the safety of drugs, devices, vaccines, and medical procedures. Current studies include post-marketing safety studies for recently approved drugs, natural history of disease studies to provide context for Phase III clinical trials, studies of the impact of drug labeling and warnings on prescribing behavior, and determinants of drug uptake and discontinuation. Additional areas of research and expertise include health effects of chemicals used in the workplace and statistical methods in epidemiology. Dr. Walker received an MD degree from Harvard Medical School in 1974, and a doctorate of Public Health in Epidemiology from the Harvard School of Public Health in 1981. Dr. Walker is associate editor of Pharmacoepidemiology and Drug Safety and is on the Board of Directors of the International Society for Pharmacoepidemiology, which he also served as President in 1995-1996. He was a statistical consultant for the New England Journal of Medicine from 1992 through 1996 and a Contributing Editor of The Lancet from 1999 through 2001. From 2000 through 2007, he served as Senior Vice President for Epidemiology at Ingenix. Dr. Walker has written or contributed to over 250 peer-reviewed articles in drug safety, epidemiology and occupational health, and is the author of a book of essays, Observation and Inference: An Introduction to the Methods of Epidemiology.

Deborah S. Hennessey has managed scientific research and consulting for over 25 years, with a focus on meticulous planning, adequate resourcing and close attention to the needs of clients, consultants and staff. Ms. Hennessey directed operations for the start-up research firm Epidemiology Resources Inc. from inception until its sale in 2000 to Ingenix, where she rose to Vice President for Operations in the epidemiology group.